There's nothing I try to get at. It just for a change of pace. Don't you feel sometime like watching an action movie or a romantic comedy even if you prefer sci-fi? I felt like watching some stand alone episodes with high sci-fi concept this time around.I see the OP got plenty of suggestions over the weekend
All that said, to the OP - not sure what you are getting at here,
Anyway there's no episodes in any TV shows beside sci-fi anthology that are truly stand alone even in TOS, TNG and Voyager. They all bring us some new insight into the characters reactions to events or the world they inhabit. Hard Time was a high sci-fi concept mostly stand alone but it still brought us intense character drama for miles and somehow we learned more about him and also try to imagine how we would react in similar situation.
By watching many episode of season 5 lately. I think almost every episodes got a stand alone component (a story with a beginning a middle and an end) and are part of the bigger overall story and character arc at the same time. My preferred kind of TV show. I think DS9 fans tend to exaggerate the serialized nature of the show if I use season 5 as representative of DS9.
Thank you for people who posted their suggestions for high sci-fi concept stand alone episodes. I've (re)watched a couple of them already. If you got some more, you can keep them coming.